1. Field of the Disclosure
This disclosure relates generally to estimating orientation of a liner conveyed in a wellbore and deploying the liner based on such orientation.
2. Background of the Art
Oil wells (also referred to as “wellbores” or “boreholes”) are typically drilled with a drill string having a drilling assembly (also referred to as a “bottom hole assembly” (BHA)) at the bottom end of a tubular member (such as a jointed pipe or coiled-tubing). A drill bit is attached at the end of drilling assembly to drill the wellbore. Once the wellbore has been drilled, the drill string is retrieved to the surface and a casing is set in the wellbore to avoid a collapse of the wellbore. Such a method requires removing the drill string from the wellbore before deploying and setting the casing in the wellbore.
Wellbores are sometimes drilled wherein a liner is placed outside the drill string. The drilling assembly used for such operations includes a drill bit (referred to as the “pilot” bit) to drill a small diameter hole followed by an underreamer (a larger diameter drill bit) which enlarges the pilot hole to a size greater than the outer dimensions of the liner. The drilling assembly is retrievably disposed at or below the liner bottom so that it can be retrieved without retrieving the liner. The liner is set in the wellbore after drilling the wellbore.
Many wellbores include sections of different inclinations and curvatures. Some wellbores are further developed by drilling lateral wellbores from the initial or main wellbore. In some cases, it is desirable to form features, such as windows for drilling lateral wellbores, in the liner before it is deployed in the wellbore so as to avoid secondary operations, such as cutting a window in the liner. These and other features can be formed at the surface with greater precision and at a relatively low cost compared to forming such features in the liner after the liner has been deployed in the wellbore. The orientation of the features formed at the surface relative to the drilling assembly or the drill string is known before the deployment of the liner around the drill string. However, due to the relatively long length of the liner and the rotational forces to which it is subjected in the wellbore, the relative location of these features with respect to a known location on the drilling assembly is subject to change.
The disclosure herein provides apparatus and methods for estimating orientation of a liner in the wellbore and taking one or more actions based on such estimate.